Author(s): Obada Nairat, John F. Beacom, Kevin J. Kelly, and Shirley Weishi Li Matter-induced neutrino flavor mixing (the Mikheyev-Smirnov-Wolfenstein, or MSW, effect) is a central prediction of the neutrino mixing framework, but it has not been conclusively observed. Direct observation of the energy-dependent MSW transition in the solar electron-neutrino survival probability … [Phys. Rev. Lett. 137, 081801] Published Wed Aug 19, 2026